This invention relates broadly to portable assemblies comprising an electrometric radiation dosimeter and a charger therefor. More particularly, it relates to such assemblies including a battery-free charger.
As is well known, electrometer-type dosimeters require charging to selected degree before use and re-charging after extended storage or exposure to radiation. There is a continuing need for a manually operated, portable dosimeter charger which is reliable, rugged, and relatively inexpensive. U.S. Pat. No. 4,247,775, which issued to S. Kronenberg on Jan. 27, 1981, discloses a dosimeter charger in which a charging voltage is produced by manually generating a force which is applied to a piezoelectric crystal. U.S. Pat. No. 2,761,063, issued to L. E. Carlbom et al on Aug. 28, 1956, discloses a radiation dosimeter provided with an integral charger which generates electrical charges when shaken. Co-pending, co-assigned U.S. patent application Ser. No. 343,607 discloses a pocket radiation dosimeter and a non-electrostatic charger therefor. The structure and operation of electrometer-type dosimeters and battery-operated chargers therefor are described in various publications, such as the following: Repair and Maintenance Manual for Civil Defense Radiological Instruments, Vol. 4, Office of Civil Defense, Washington, D.C. The foregoing publications are incorporated herein by reference.
In some dosimeter applications, it is important that the dosimeter-charging operation be made as simple and reliable as possible. Conventional shake-type electrostatic chargers are deficient in these respects because they generate voltage outputs of variable polarity, with the result that initial zeroing of the dosimeter is somewhat difficult and time-consuming. That is, one shake of the generator may drive the image upscale whereas the next may drive it downscale.